Affiliate disclosure: We may earn a commission if you make a purchase through these links at no extra cost to you. For more info, visit our disclosure page.

Here’s what happens when your terrarium has too much water

If you’ve done any research into caring for terrariums, you’ve probably heard people mention overwatering. But what exactly is over-watering and why exactly is that bad for your terrarium? That’s something I’ve been wondering about myself.

Overwatering your terrarium plants is almost like drowning your plants. Plants need oxygen too. Some symptoms of cutting off your plant roots’ access to oxygen include drooping, yellow leaves, brown tips, root rot, mold growth, and leaves falling off your plants.

That’s the bad news. The good news is that there are a few ways that you can identify overwatering and respond early before it does too much damage.

What overwatering does to your plants

So let’s back up a little bit.

One thing a lot of people don’t realize about plants is that they actually need oxygen. Plants respire just like animals do. It’s a process that produces energy for their cells by breaking down sugars while consuming oxygen. You can think about it like reverse photosynthesis.

They get that oxygen through their roots when they are exposed to small pockets of air in the soil.

When you overwater your plants, you are essentially smothering your plant roots with water. This stops them from being able to absorb oxygen or “breathe” if you will.

If this goes on for too long, this will lead to visible, undesirable symptoms:

  • Root rot (paired with a nasty smell)
  • Mold growth
  • Droopy plants
  • Yellow or brown leaves and brown tips
  • Leaves falling off

But don’t take it too personally if it does happen. Just think about it as your plant telling you that something’s wrong.

How to tell your terrarium is overwatered

So if you look through the list of symptoms above, those can serve as indicators that overwatering might be a problem in your terrarium. 

Fortunately, you don’t have to wait until you start seeing the problem to identify when your terrarium is overwatered. There are actually a few ways you can check for over-watering before it does too much damage. 

Excessive condensation usually means too much water

If your terrarium is being overwatered, the most obvious sign that you’ll see is that there is heavy condensation 24/7 in your terrarium.

This will probably be most apparent shortly after a watering session.

Ideally, your terrarium should only be experiencing a bit of condensation in the mornings and evenings.

If you notice this, you can open up your terrarium and wipe off the excess condensation while leaving it open for a few hours to air out.

Soggy soil usually means too much water

Periodically, you can check the soil by giving it a light touch.

If the soil feels soaking wet or soggy, your terrarium probably has too much water.

Ideally, the soil should feel slightly moist, but not bone dry or soaking wet.

If the soil feels a little too wet for your liking, you can take a piece of paper towel and press it down on the soil to remove excess water. You can even leave it in there for a day or two to soak up a bit more water. 

If your paper towel is getting soaked, that’s a good sign that you’re getting a lot of the water out of your terrarium. You can take it out once you feel like the paper towel soaked up as much as it can.

Frequent watering sessions probably means too much water

If you’re the type of person who likes to actively care for their terrarium by watering it often, that’s probably a sign you’re terrarium is overwatered.

A closed terrarium shouldn’t need to be watered more than once every few months at most. They may not even need to be watered at all after the initial setup.

In a closed terrarium, the water cycles itself within the container. So there’s no need for you to add any more additional water to the system.

Open terrariums in general don’t need too much water to begin with. They will need water occasionally but they will probably tolerate a little bit of underwatering better than overwatering.

If you’ve been watering your terrarium once a month or more, it’s time to consider cutting down on the watering sessions.

How to avoid overwatering your terrarium

There are a few other things you can do to prevent overwatering besides watering your terrarium less often.

Remove moisture from your terrarium if needed

The simplest way to address overwatering is to remove excess moisture from a terrarium.

The easiest way to do this is to just open up your terrarium and let’s moisture naturally evaporate over a day or two depending on how overwatered your terrarium is.

You could also get a piece of paper towel and wipe off any excess condensation in your terrarium. While you’re at it, you can also pat down the soil to soak up any excess moisture in the substrate.

Use soil with more porosity to increase drainage

When your soil is compacted, it’s easier for water to accumulate and suffocate your plant roots. This can happen with high moisture-retaining substrate material like coir or peat moss.

When you increase the porosity, water drains more easily and there will be more air pockets for your plant roots to get oxygen.

The net result of this is that the effects of excess water will be offset by the increased drainage and aeration in the soil.

To increase the porosity, you can add some perlite, vermiculite, lava stones into your substrate mix.

Measure the moisture levels with a water meter

If you want to be really precise, you could use a water meter to measure the water levels in the soil directly with a water meter.

In my opinion, this isn’t entirely necessary because there are other ways to tell when your terrarium is overwatered that work just fine. But it can help you quantify how much moisture is too much.

Water your terrarium by Misting instead of pouring

If you’ve been getting a cup of water and just pouring water into your terrarium, there’s a greater risk of underestimating how much water you’re adding to your terrarium.

A mister or spray bottle can help you water your terrarium evenly with much greater control compared to pouring water.

Ultimately, what it comes down to is just being aware of how much water you’re actually giving your terrarium. If you stay aware of the signs of overwatering, you’re already most of the way there to having a perfectly watered terrarium.